INTRODUCTION. xv 



analogues to the Amphitheres and Phascolotheres of our 

 oolitic strata. 



If ever the first types of the primary groups of the class 

 Mammalia radiated from a common centre, it must have 

 been at a period incalculably remote, and there is small 

 hope of our ever being able to determine its site, by reason 

 of the enormous alternations of land and sea that have come 

 to pass since the class was first introduced into our 

 planet. We find, however, that, from the period when 

 the great masses of dry land assumed the general form 

 and position that they now present, the same peculiar 

 forms of Mammalia characterized their respective Faunae : 

 and the evidence of the distribution of the recent and 

 extinct pliocene Mammalia favours the conclusion that New 

 Zealand, Australia, South America, and the Old World 

 of the geographers had been as many distinct centres of 

 creation. 



By the same evidence we are compelled to admit, that 

 the difficulties which beset the Linnsean view of the actual 

 diffusion of organized beings * are insurmountable. Ac- 

 cording to the hypothesis that all existing land animals 

 radiated from a common Asiatic centre within the historical 

 period, we must be prepared to believe that the nocturnal 

 Apteryx, which is neither organized for flying nor swim- 

 ming, migrated across wide seas, and found its sole resting- 

 place in the Island of New Zealand, where alone the re- 

 mains of similar wingless birds have been found fossil : 

 that the Wombats, Dasyures, and Kangaroos as exclu- 

 sively travelled to Australia, where only have been found, 

 in pliocene strata and bone caves, the remains of extinct 



* See Linnaeus' preface to the ' Museum Regis Adolphi Frederici,' 1754 : and 

 the excellent remarks in Dr. Pritchard's ' Physical History of Man,' vol. i. 1826, 

 pp. 16,81. 



